arcsin定义域是[-1,1]所以-1<=√(x²-1)+1<=1-2<=√(x²-1)<=0则只有√(x²-1)=0x²-1=0但分母不等于0所以定义域是空集
1;当y大于2,即cosx小于等于1,x属于R,当y小于2大于0时,即cosx小于1大于0,所以X属于【2kπ,π/2+2kπ】并【3π/2+2kπ,2π+2kπ】,当y小于0大于-2时,即cosx小于0大于-1,所以x属于【π/2+2kπ,3π/2+2kπ】希望对你有帮助